Duolingo.com

I love this app!

I don't usually download apps on my phone, but this is the one I use every day. I took four years of Spanish in high school, but since then, I've done nothing with it. I can read OK (sort of like speaking in broken Spanish. I try to make sense of it, mostly guessing at the vast number of words I don't know or don't remember). But since my husband introduced me to this app a couple of months ago, I can't put it down. 

It's an app that teaches you a foreign language.

It offers courses in a variety of languages (fifteen), mostly European languages, and there are twelve more languages in the works.

Select the language you want to learn, and you're on your way.

It starts with very basic skill and then go on to more advanced skills.

I'm at level 11 in Spanish, but at level 1 in Russian and Irish. I thought about doing all three languages at the same time, but I found that I got quite confused and couldn't retain as many words. So, I decided to concentrate on one language at a time.

This screen shot is about a translation questions, but there are vocabulary questions (writing the meaning down as well as pairing exercises), along with enunciation questions.

I do Duolingo on my phone, so I don't have access to this Spanish words learned list (at least I haven't found it on my phone), but I don't think this feature matters much. You can finish a lesson in less than five minutes, repeating a few select words and sentences at a time. I found this very effective.

My son and daughter have picked up on duolingo (both choosing German), and they like it. My son says Duolingo is better than Rosetta Stone (which my husband and I purchased for them to learn another language). 

So, if you have five or ten minutes to kill, this might be a good way to spend your time.

Bridge Building Series - Truss Bridge 2

Truss Bridge 2 – Straws & tape (A challenge project)

This project needs more accurate taping, which might be a tad difficult for primary students. However, I've done this project with a group of 3rd graders, and they were able to build sufficient truss bridges.

Supplies:

·         A bag/box of straws

·         Tape

·         Scissors

·         Small cups

·         Paper clips

·         Weights – pennies, paper clips, etc. Anything is OK as long as they weigh the same. You want to compare how much different bridge designs can support

    

Instructions:

1.      Cut a bundle of straws to same size (~2 1/2 inches long). Leave some for different lengths. These will be cut to size.

2.      Tape four pieces together to make a square. Tape uniformly across all places. Create enough square to span an opening that is 10 inches wide.

Created bottom of the truss bridge first, then continued to build the sides of the bridge. (These squares measure to 11 inches in length.)

3.      After creating several squares, put cross bracings diagonally (cut these to size).

4.      Put the top pieces last and enclose the truss bridge.

5.      Place the truss bridge between two desks, tables, chairs, etc.

6.      Hang a small cup in the middle of the bridge (use hole puncher and paper clips) and load it with pennies, paper clips, etc. to weigh it down and test its strength.

Same amount as beam bridge

Added more coins

Added another bucket full of coins.

7.      Different size straws, too much tape on one side vs. the other side, etc. will create imbalance and weaknesses in the bridge structure. Try to balance taping, straw usage, etc. on all sides.

This straw and tape truss bridge was much stronger than I expected. I think I could have added another bucket of coins, but I ran out of bridge space. Maybe you can build a longer bridge and test how many buckets of coins your bridge will hold. Of course, the longer the bridge span, weaker the bridge. So, you might have to consider the bridge span vs. support strength of the abutment.

Remember, Engineering is all about failing and trying, again. So, try and try, again.

Tech Challenge 2016 Recap 3 (Test Trial Pix)

In this Tech Challenge 2016 recap series, we'll be following a group of fourth graders who entered the tech challenge for the first time.

One of the most important things to do when participating in the tech challenge is to attend at least one test trial at the Tech Museum of Innovation in San Jose, California. This 4th-grade team has attended  3 test trials this year. 

Here are some pictures of our 4th-grade team at the test trials they've attended in the Tech Challenge 2016 competition.

1st Test Trial

1st Test Trial

2nd Test Trial

2nd Test Trial

3rd Test Trial

3rd Test Trial

At each test trial, the teams initially test their proof-of-concept and then go on to test and improve their prototypes until the competition day. It also provides an occasion for the judges to check if the teams meet the technical requirements of the tech challenge. The more you attend, the more data a team has to improve its designs and eliminate the design and performance issues.

Maybe we'll see you next year.

Bridge Building Series - Truss Bridge 1

Truss bridge building instructions 1

We’ll make different truss bridges using two different materials - foam cubes and cut drinking straw pieces.

Design Rules for both bridges:

1.      Bridge must span 10 inches (25 cm)

2.      Bridge must have a place to attach a small cup in the center of the span (preferred).

3.      The ends of the bridge are not taped onto the support structure.

Bridge 1 – Marshmallow/foam cubes/cheese balls & toothpicks

NOTE: The best material for this project is foam cubes. However, a container of foam cubes can get very expensive (I've paid $27.49 for a container of 105 foam cubes), so if you can find more affordable ones, please let me know.

I've done this project with marshmallows, and it's doable (for intermediate grades). And cheese balls get messy, but doable as well.

Supplies:

·         A bag of marshmallows, foam cubes, or cheese balls

·         A box of toothpicks

·         Tape

·         Small cups

·         Paper clips

·         Weights – pennies, paper clips, etc. Anything is OK as long as they weigh the same. You want to compare how much different bridge designs can support

    

Instructions:

1.   Create a square with four foam cube pieces and toothpicks. Create 3 more. Put them together to create a cube. 

2.   Create several more cubes and put them together until you reach 10 inches in length. Remember, your bridge must be longer than the span it needs to bridge (add an inch or two to the total length of your bridge).

  

3.   Place the bridge between two desks, tables, chairs, etc.

4.   Hang a small cup in the middle of the bridge (use hole puncher and paper clips) and load it with pennies, paper clips, etc. to weigh it down and test its strength.

~same number of coins in the cup as the beam bridge project

added another cup of coins

added more coins to each cup

Again, this project works best with these foam cubes. I purchased from Amazon, but they are pricey. I did find some smaller foam cubes from the Dollar Tree store, and they worked well. But it's very difficult to find them consistently. You can see them on their online store, and the store managers don't seem to know when or if they'll ever get another shipment. So, if you find another source of reasonably priced foam cubes, please let me know.

Bridge Building Series - Truss Bridge Introduction

Truss Bridges

A truss bridge is a bridge that bears its weight through its truss system. This truss system is composed of triangles that give its strength.

 

Truss bridges are one of the oldest types of modern bridges and are more economical to build than solid beams with additional support structures on the bottom.

Most commonly used truss bridge designs are Pratt, Warren, and Howe, but engineers have used many different truss patterns in bridges.

        

Cantilever bridges are beam bridges that are supported on only one end. These type of bridges often use a pair of spans that extend from opposite sides of the supporting structures to and meet in the middle. This bridge feature allows ships and other superstructures to pass.

Truss bridges can be made with all kinds of materials. The most impressive ones I've seen so far are the bridges made with popsicle sticks and glue; however, I try to minimize the mess in classrooms, so my truss bridges are made with foam cubes and straws.

Have a great day. 

Tech Challenge 2016 Recap 2

Here are some of the designs a fourth-grader team designed and built over the course of the Tech Challenge 2016.

A team member got this glider idea from the Maker magazine. It was a good start to learn about gliders and center of gravity.

Comparing the flight of our bird gliders to the store-bought balsa wood gliders.

We got the idea from one of the library books a team member borrowed from the library. This glider is made out of  foam plates.

The same design different material. Foam gliders flew better than the paper plate gliders.

The goal for our team is to research (online, library, books, magazines, etc.) and learn about the subject matter as much as possible. We also watch a lot of youtube videos, too. 

Try some of these with your kids today.

Awesome Books - Physics of the Future by Michio Kaku

I love this book because it helps me believe in one of my biggest passions – space travel. After I had taken a class in Astronomy in junior high school, I wanted to be an astronaut. Alas, it wasn’t meant to be because I suffer from motion sickness.

I am curious by nature. I want to know about everything, albeit salt or germs or black holes or dark matter. And this book answers my questions in spades. Whether it’s about force fields or invisibility or perpetual-motion machine or precognition, this book answers all. The best thing about it is that the answers are anchored in science, and Michio Kaku gives his best guess time frame for them to become a reality.

As for accessibility and easy to digest part, I recommended this book to a ten-year-old who was very interested in Science, and not only did he finish it, but he said it was interesting. He did have trouble understanding parts of it, and his parents tried to help him understand those parts.

This book helps me believe the possibility in things that are deemed impossible. Michio Kaku does frame some of them in very, very long time (might as well be impossible), but he gives us a realistic time frame. That’s the point I appreciate.

I would highly recommend this book to anyone who is interested in a long list of topics that seem to skirt the science fiction side of science (phasers and death stars, teleportation, telepathy, psychokinesis, robots, ETs and UFOs, starships, anti-matter and anti-universe, faster than light, time travel, and parallel universe, etc.). I’m not sure I’d recommend it to another ten-year-old, but you’d know if that child is ready for this or not, so I’ll leave that to you.

PS - the ten-year-old read it again (he's no longer a ten-year-old), he said he'd recommend to 8th grade and up students.

I do have this book listed on my Books I love blog with a slightly different post.

Bridge Building Series - Arch Bridge

Arch Bridges

Arch bridges have extraordinary strength due to their shape.

Unlike a beam bridge, the weight and the load on an arch bridge are pushed outward and carried along the curve to the support structures at each end called abutments.

An arch bridge carries all loads in compression, without any tensile forces. The stones in an arch bridge stay together by the force of their weight and the compressive force transferred between them. 

The size of the arch directly affects the effectiveness of an arch bridge. The arch is flattened down in very large arch bridges and large tensile forces that must be factored into the bridge design.

A simple arch bridge experiment

Supplies:

·         A ¼ piece of cardstock paper

·         A permanent marker

·         A ruler

·         A stack of books to wedge in the paper

Building instructions:

1.   Draw lines 1/2” apart on the cardboard or cardstock paper. 

2.   Wedge it between a gap created by books, chairs, desks, or other objects.

3.   Tape the ends onto the books, desks, or other objects.

4.   Now, press down on any part of the arched cardboard or cardstock paper. What happened? What is happening with the lines on the cardboard?

Top View

An arch bridge without an additional load.

An arch bridge with some load. It still holds its shape well.

An arch bridge with considerable load. It still holds its shape pretty well.

An arch bridge in danger of collapsing. The arch has flattened out too much.

Bottom View

An arch bridge with very little load. It holds its shape well.

An arch bridge with more load. It holds its shape well, again.

An arch bridge under considerable load. Its arch is beginning to flatten out a bit.

An arch bridge in danger of collapsing. The arch has flattened out too much.

Again, this is a very simple project, but it does an excellent job of demonstrating what an arch bridge experiences under load.

        

Tech Challenge 2016 Recap 1

I've been an advisor to a tech challenge team for four years, and this was the most difficult challenge to date. 

The 2016 challenge: Build a glider to deliver supplies to a remote location!
This year, you tell the story! What is your glider carrying? Where are you going? Why?
New award for 2016: Top Tech Challenge story! 
Who: Students in Grades 4-12
What: A team engineering design challenge
When: Event Days are Saturday, April 23 (Grades 4-6) and Sunday, April 24 (Grades 9-12 and Grades 7-8)
Why: To develop creative solutions to a real-world problem

A glider, which weighs less than a pound, must carry payloads (ping pong balls), gain 6 inches of lift in 6 feet, make a turn around a storm column, and deliver payloads to a "remote" location 26 feet away.

Not only did teams have to build their gliders, but they must incorporate a launcher, which will have a trigger mechanism. Then it's got to gain lift and turn. What a challenge for a fourth-grade team.

Yes, since last year, the Tech Challenge has been opened to fourth graders, and it was a welcome change for those kids who were eager to form their own teams after watching their older sibling's teams compete for years.

A 4th-grade team was talking with the judges at a test trial at the Tech Museum. You can clearly see the launch platform, the mountains, and the storm column that the glider must clear before landing on the target (26 feet away) successfully.

The glider must be launched at 0 degrees launch angle and have a trigger.

I think elementary students, as young as Kindergarten students, can get a lot out of this program, but I think the fourth-grade cut-off is a logical one, especially with the Engineering Design Journal requirement.

I didn't have the time to blog about this great program while it was in progress. Next year, I'm going to put forth extra effort to blog about this AWESOME program in more timely manner.